1. Field of the Invention
The present invention relates to a Multiple Input Multiple Output (MIMO) system. More particularly, the present invention relates to a method and apparatus for detecting control channels in a MIMO system.
2. Description of the Related Art
Mobile communication systems are developed to provide subscribers with voice communication services on the move. With the rapid advance of technologies, the mobile communication systems have evolved to support high speed data communication services as well as the standard voice communication services. However, the limited resource and user requirements for higher speed services in the current mobile communication system spur the evolution to more advanced mobile communication systems.
Long Term Evolution-Advanced (LTE-A) is a next generation mobile communication standard under development to meet such user requirements. LTE-A is being standardized by the 3rd Generation Partnership Project (3GPP). LTE-A is a technology for realizing high speed packet-based communication at up to about 1 Gbps. In an effort to achieve this, discussions are being held on several schemes such as network multiplexing for deploying multiple evolved Node Bs (eNBs) overlappingly in a specific area and increasing the number of frequency bands supported by an eNB.
Meanwhile, LTE operates with control channels designed based on a distributed transmission mode. The distributed transmission-based design aims to reduce inter-cell interference, distribute interference, and achieve frequency diversity gain.
However, LTE-A assumes there is an operating environment with very short inter-cell distance and high inter-cell interference. Accordingly, in the distributed transmission mode-based control channel design, inter-cell interference is inevitable.
LTE-A is also capable of adopting a control channel transmission mode exploiting frequency-selective gain. This is advantageous in that the control channel can be transmitted using a lesser amount of resources, but is also disadvantageous in that the terminal is likely to fail to receive the control channel, especially when the channel varies frequently. The evolved system supports both the related-art frequency diversity gain-oriented transmission mode and frequency selective gain-oriented transmission mode. The frequency-selective gain varies dynamically according to the status of the terminal. Also, there can be a control channel to which only one of the two transmission modes is employed, i.e., frequency-selective gain-oriented and frequency diversity gain-oriented transmission modes.
Accordingly, the system should support both the aforementioned transmission modes, frequency-selective gain-oriented and frequency diversity gain-oriented transmission modes, in control channel transmission without compromising terminal complexity. This means that there is a need of a control channel detection method for the terminal to acquire the configuration information on the new control channel structure.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.